Solar collectors, as found in Israel and other locations, are typically made of metal structures comprising metallic pipes and covered by a glass pane, and are disposed in an inclined orientation. An inlet manifold at the bottom of the solar collector provides feed water that rises in thermosiphon tubes to an outlet manifold at the top of the collector from which the water exits the solar collector.
Solar collectors comprising polymeric materials are also known, as related, for example, in U.S. Pat. Nos. 4,114,597 and 4,082,082, the disclosures of which are incorporated herein by reference.